Hitachi tunes 8-bit MCUs for Web server apps

LONDON  In a move that could set the stage for ubiquitous Internet connectivity, Hitachi Europe Ltd. is working with LiveDevices Ltd. (York, England) to provide a real-time kernel and TCP/IP stack that fits in the ROM of Hitachi 8-bit microcontrollers. The effort is intended to help engineers build such items as Internet-connected washing machines, refrigerators and vending machines.

The project has the two companies struggling with some fundamental issues of in-service microcontroller reconfiguration and security. The attraction is a worldwide market for Internet appliances that International Data Corp. has estimated will be worth around $17.8 billion in 2004.

To reserve a place in that market, LiveDevices has rolled out its Embedinet software development kit, with a real-time kernel and a TCP/IP stack that can be used royalty-free. Originally developed for the PIC18CXXX family of 8-bit microcontrollers from Microchip Technology Inc., the kernel and stack have been ported to the Hitachi H8S microcontroller family, with support for the H8/300H Tiny variants to follow. The software development kit is available for a license fee of about $3,550.

On top of the real-time kernel and TCP/IP stack, LiveDevices has developed a series of generic and separately licensable modules covering such functions as security, file transfer protocols, Web-page serving and remote flash-memory programming.

Today, such networking protocols are associated with computers and 32-bit processors. But according to Hitachi Europe and LiveDevices, they will increasingly be deployed on deeply embedded microcontroller applications.

The companies plan to demonstrate an H8 microcontroller video recorder operated over the Internet by the end of the first quarter of 2002.

"Many applications today are still 8-bit, and the developers of those applications are looking for product differentiation," said Graeme Clark, senior product-marketing engineer with Hitachi Europe. "For example, washing machines are a low-cost product, and it is just not possible to justify a 32-bit core and system-chip implementation."

"It's not the die area that prohibits it so much as the manufacturing implications and the development costs," said Nick Keeling, director of product marketing at LiveDevices.

"The Embedinet strategy is about getting costs down to $5 but allowing customers to add much more value to their embedded device," Keeling said. "For example, it is possible to make the product more capable or to offload the smarts into the network cloud and give vendors the option to sell an additional service."

To allow such Web serving and file transfers to take place through an 8-bit microcontroller, LiveDevices has turned its attention to extremely small-footprint programming. The Embedinet real-time kernel, for example, offers priority-based preemptive scheduling of multiple tasks and intertask communication in 1.2 to 1.5 kbytes of ROM and requires just 20 bytes of RAM, Keeling said.

Small-footprint version

A full implementation of Internet Protocol, Transmission Control Protocol, User Datagram Protocol and Internet Control Message Protocol  with Serial Line Internet Protocol and Point-to-Point Protocol data transport layers  is included in the associated Internet connectivity stack. Keeling said that the TCP/IP stack occupies 2,100 bytes of ROM with an additional 28 bytes of RAM required per connection supported.

"This is not a desktop solution pared down but a small-footprint version built from the ground up," he said.

Higher-level modules also available for licensing, and bearing royalty fees, are called File (FTP and TFTP), Time (Simple Network Time Protocol), Name (DNS client) and E-mail (Simple Mail Transfer Protocol client).

A licensable Web server provides an implementation of HTTP to enable an embedded device to serve Web pages as required. Other modules cover remote flash-memory reprogramming and security.

Remote reprogramming

"The reprogramming of flash remotely could be one of the most powerful developments," said Keeling. "For example, a vending machine manufacturer may want to update the price list. We are also looking at the updating of control ROM to be used for remote bug fixing or to introduce a version update. Anything that saves truck rolls is interesting to customers."

Flash, in fact, is "one of Hitachi's great strengths," said Hitachi's Clark. "It could be external, but mainly we are looking at internal-flash, single-chip applications."

But security is likely to be a primary concern for potential users. For vending machines, LiveDevices is developing a secure data transfer module to minimize the possibility of unauthorized viewing of information. "Security has to be a fundamental part of Embedinet from the ground up," said Keeling. "You can't use the Secure Sockets Layer; it's way too heavyweight."